Method of making a tubular pin



May 116, i933 w. J. GAGNON I METHOD OF MAKINGA TUBULAR PIN Original Filed Sept. '11, .1928

. INVENTOR WILLIAM J. GAGNON 2y hzs aZ-Zvrnga Patented May 16, 1933:

UNITED STATES:

PATENT WILLIAI J. GAGNON,

MANUFACTURING COMPANY, OF CONNECTICUT or nnmonronr, connncrrcwnhssrenon 'ro run nmnenroar, oonnnc'rrcu'r,

a conron ario METHOD 0! MAKING A TUBULAR PIN Original application tiled September 11, 1928, Serial No. 305,898, new Patent No. 1,812,748, dated June 30,

I be given vision.

1981. Divided and My invention relates to tubular pins, especially pins made of sheet metal and closed with a longitudinal seam such as are used as contact pins for radio tubes and it is an object of this invention to provide an improved method of manufacturing pins oi the class described.

Heretofore when pins formed of sheet metal and closed with a seam have been molded into the insulation forming the base of a radio tube the pressure under which this has been done has been sufiicient to cause the head of the pin to open at its seam and allow some of the insulation to leak into the pin. Since it is customary to pass a wire conductor through such a pin after the pin has been molded into the base of the tube and solder the end of the conductor to the lower end of the pin, the presence of insulation within the pin is objectionable as such material within the pin obstructs the passage of the conductor in the pin. Furthermore, the present process of molding pins into insulation bases of such material for instance as bakelite, makes it necessary to use a conically shaped punch in a process well-known in the art. In this process the punch may spread open the seam of the pin as it travels downward to press the insulation into shape thereby causing leakage suflicient to impair the usefulness of the pin. I have discovered that if the top of the pin a special shape and if a cap, having no seam, be closed over and suitably attached to the pin top, this leakage of insulation may be completely eliminated and a stronger and more'useful pin produced.

A pin of this type'is described and claimed in my prior application Serial No. 305,296, filed Septemberll, 1928 which resulted in Patent 1,812,743, issued June 30, 1931 of which application this application is a di-' In the drawing- Figure 1. illustrates a method of making the capped tubular pin the apparatus being shown ready to press the cap upon the pin r;

Figure 2 shows the parts illustrated in Fig urel-as the cap is attached to the pin top;

this application filed Karel: 2, 1981. Serial No. 519,616.

Figure 3 is a sectional elevation of the pin and cap; and

Figure 4 is an elevation of the capped pin with its top unched, the upper part of the pin and cap ing shown in section.

In the embodiment of the invention illustrated in the drawing, there is first formed a sheet metal tubular in having a seam running longitudinally t ereof. An abutment shoulder 11 is formed integrally with and surroundin the pin. The top of the pin 10 is necked own or tapered slightly on one side of and toward the abutment shoulder. In other words the pin is given a smaller diameter above the abutment shoulder 11, as best illustrated in Fig. 3. A neck 12 is thus formed completely surrounding the pin.

A; cap 13 closed at one end and having a cylindrical skirt, somewhat like the metal- 110 shell of a cartridge and best seen in Figure 3is placed over the top of the pin, and

a cap 13, which strengthens the in and closes the seam above the abutment s oulder.

The preferred method of capping the pin is illustrated in Figures .1 and 2 in which the caps 13 are fed from a chute 14 into a feeding slot 15, along with a plunger 16 moves each cap into position on t e in end, while the pin is held in dies 17: he conformation of the dies adjacent the pin head is that of the pin head with only suflicient clearance being left between thedies and the pin head to receive the cap so that the cap 1s shaped to conform to the pin head as it is forced onto the pin head. This contracts the portion of the cap adjacent the free edge thereof about the neck of the pin and secures the cap firmly in place on the pin. Figure 2 shows the position of the cap a ter the plunger 16 has forced it into place about suited for being molded into. radio tube duced diameter a of the portion of the pin on whic bases. As is well-known, only the top of the pin, as far down as the abutment shoulder, is molded into the tube base. The pin top being surrounded by an unbroken cap permits no leakage into the in top of the material into which it is mol ed. Furthermore, when the usual comically-shaped punch is applied to the pin top to open up a wire way, and press the molded base into shape, it does not open the seam and permit leakage into the pin. Instead it pierces the cap top and makes a erfect v ve seat in its downward travel. akage of the tube base material into the pin is thus prevented. (See Fi re 4.) Y ins constructed in accordance with the present invention, therefore, will be seen to be free from the objections to which other sheet metal pins are subject, in that the insulation will not leak into them during the process of molding and their strength will be sufiicient for all practical purposes. The process of capping the end 0 the pin is simple, effective and inexpensive, and many of the advantages of the solid pin are present in sheet metal pins constructed in accordance with the, invention.

With the understanding that the specific description and illustrations are givenmerely to indicate how the invention may plied.

I claim 1. A method of forming a capped pin comhe apprising shaping a pin with a portion of re-- duced diameter ad acent one end, applying a cap to said end and shaping the cap to conform to the portion of reduced diameter as the cap is moved'longitudinally of the pin on the end of the pin while retaining the shape of the ortion of the pin to which the cap is applied.

2. A method of forming a capped pin cornprising shaping a in with a portion of re 'acent one end, shaping a ca to fit said poi tion of reduced diameter whi e moving the cap longitudinall of the pin on the said end and retaining t e shape the cap is placed during the shaping of the cap thereto.

3. A method of forming acapped seamed tubular pin comprising shapin fromsheet metal a pin tapering inwardly rom one end, applying a cap to the tapered end and shaping the cap to conform to the tapered end as the cap is moved longitudinally of the pin on the tapered end of the pin. 3

4. A method of forming a capped pin comprising shaping a pin which tapers inward'l from one end to a contracted neck and simnl taneously moving a cap longitudinally of the pin on said tapered end and tapering the cap to fit the tipered end of the pin.

' In the me od of forming a capped pin the step'of simultaneously moving a cap longitudina-lly of the pin on a head of the pin on the the pin 6. In the method of forming acapped in,

the step of simultaneously moving a cap ongitudinally of the in on an inwardly ta red end of the pin an shaping the cap to ht the tapered end of the pin. A method of forming a capped in comprising forming a pin with a head shaped to retain a cap and simultaneously shaping the cap to fit the pin head while forcing the cap pindhead and retaining the shape of 8. A method of forming a capped pin comprising shaping a pin with an inwardly tapering end portion, applying a tubular cap to said pin and tapering said tubular cap to fit said tapered end portlon of said pin as the cap is forced lon itudinally onto said pin.

9. A. method o forming a capped pin comprising shaping a pin with an inwardly tapering end portion, applying a cap having 'a tubular skirt portion and tapering sai tubular skirt portion tofit the tapered end portion of the pin as the cap is forced longitudinally onto said pin.

10. A method of forming a capped pin comprising shaping: a pin with an inwardly tapering end portion, applyin a cap having a cylindrical skirt portion an sha ing said cylindrical skirt portion throu out its length to fit the tapered end portion of the pin as the cap is forced longitudinally onto said pin. In testimony whereof I have name to this specification.

WILLIAM J. GAGNUN.

signed my lld are 

